Last night on Late Show with David Letterman, Brian Williams breaks character and impersonates the “plush toyâ€â€“size Regis Philbin. Plus: Neil Patrick Harris contemplates sex with Smurfs — “You took it to a place of degradation I didn’t even dream of,†responds Jon Stewart; the almighty Judd Apatow turned Emma Stone from a blonde to a redhead; and Jimmy Fallon misinterpreted Don Cheadle’s look and danced for him. Watch our compilation to see what you missed.